The aim of the present work is to investigate the situation of solid waste management in Tehran and compare it with Beijing. This paper presents the electricity production potential of methane from waste collected and greenhouse gas assessment in 16 districts from Beijing and 22 districts from Tehran in 20 years (2019–2038) using landfill gas to electricity system. Evaluation of economic feasibility was performed using Net Present Value (NPV), Payback Time (PT) and Levelized Cost of Energy (LCOE) methods. It was found that, the average methane captured from landfill in Beijing’s districts in the early and final years of the project is 62.5% and 22.74% higher than in Tehran, respectively. However, the total potential for electricity generation in Beijing's districts in the first year of the project is about 18% higher than in Tehran. Moreover, the average NPV for the urban districts of Beijing is 60.3% more than that in Tehran. Meanwhile, the average PT and LCOE for the urban districts of Tehran are 1.1 years and 13.15% higher than that for Beijing, respectively. Also, the use of technology in the densely populated districts of Beijing has better greenhouse gas effects than the densely populated districts of Tehran.